The present disclosure herein relates to a communication system, and more particularly, to a human body communication system that uses a human body as a channel.
Human body communication uses a human body having conductivity as a channel. Data is transmitted by using a transmitter that is connected to a portion of the human body. The transmitted data is recovered by using a receiver that is connected to another portion of the human body or outside the human body. When using the human body communication, the communication between portable devices or the communication between a fixed device and a user may be performed through a user touch. For example, the communication between a portable digital assistant (PDA), a portable computer, a digital camera, an MP3 player, and a mobile phone may be performed through a user touch. Payment for the usage of a printer, a credit card, a TV, an entrance system or transportation may be performed through a user touch.
While the air transmits a radio wave uniformly, the delivery characteristic of electricity or the radio wave through the human body is determined according to the electrical characteristics of tissues that form the human body, i.e., permittivity and conductivity. Thus, the receiver that is at any portion on the human body is difficult to receive an accurate radio wave from a transmitter. The radio wave delivered through the human body loses more energy than the radio wave that is delivered through the air. Since the human body has conductivity, the human body is easy to receive an interference signal from the surrounding environment.